Which of the following is evidence of a physical change? haora

Pauling and lewis questioned the extreme definitions of bonds. they wondered if bonds might be described somewhere in between the two extremes (covalent and ionic). on the basis of experimental data,pauling confirmed that bonds could be ionic, covalent, and for those, in between, exhibit a degree of ionic character. he theorized that the major factor was how strongly the atoms in the bond attracted the electrons. pauling called this factor - the tendency of an atom to attract electrons in a bond.

Agas at 155 kpa and standard temperature has an initial volume of 1.00 l. the pressure of the gas rises to 500 kpa as the temperature also rises to 135°c. what is the new volume? 2.16 l 0.463 l 0.207 l 4.82 l

Calculate the expected ph values of the buffer systems from the experiments (a,b,c,d), using the henderson- hasselbalch equation, ph-pka+log[a-]/[ha]. use for pka values carbonic acid= 6.37, and acetic acid= 4.75.